Others indicted along with Diaz insist that none of the targeted transactions had any connection with foreign drug gangs. But a longtime investigator says he's been hearing plenty about Mexican cartels attempting to force their way into the Colorado biz, partly due to the much higher quality of pot grown and sold here.

"From what we're hearing, Colorado marijuana is a lot more desirable than the Mexican marijuana," says Tom Gormon, director of the Rocky Mountain High Intensity Drug Trafficking Area organization, RMHIDTA has sponsored studies about the dangers of home cannabis grows and the negative impacts of the state's pot experiment, among other things. "So for the cartels to compete, they have to upgrade their marijuana, get out of the business or try to get involved in the business in Colorado."

Of these three options, the first would be time-consuming and the second is improbable -- but Gorman thinks the third is a very real possibility.

Hector Diaz, who's also facing weapons-related charges.

"Our concern -- and we've had some indication of this -- is that the Mexican cartels would see this as a very lucrative business," he notes.

How would Mexican cartels go about gaining a foothold in Colorado? "One of their primary moneymaking opportunities besides drug dealing is extortion," Gorman points out, referencing a cartel attack on a casino in Monterrey, Mexico circa 2011 in which 52 people were killed. "That was not a dope deal: That was an extortion deal. They were extorting money and apparently the casino didn't want to pay -- but they paid a price for that in the end."

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"If you're a cartel member and you see ways to make money in a trade you're used to, it's a perfect storm," he allows. "Say you're a retail cultivator or a store owner. Someone from a cartel comes in and shows you a picture of your kids going to school -- and they tell you, 'I want 40 percent of your profits or you're not going to see your kids anymore.'

Continue for more of our interview with Tom Gorman about possible Mexican drug cartels forcing their way into the Colorado marijuana business.

Tom Gorman.

"Cartels are very treacherous," Gorman says. "They're no-holds-barred. With these people, they'll cut off heads, they kill kids, they'll take kids for body parts. They just put no value on human life at all. And if money is their game, you can see why they might want to get involved in the marijuana industry in Colorado."

When he's asked if there have been specific incidents like this in Colorado, Gorman alludes to "stuff we can't reveal...but based on information that we have, we've got grave concerns this could occur.

"So much of drug trafficking in Colorado is being done by Mexican drug-trafficking organizations. It's not like they're unfamiliar with this territory. Put all this together and you can see there's a real reason for concern -- and we don't need that in our state."

A photo from the Rocky Mountain High Intensity Drug Trafficking Area website.

Putting a stop to such crimes before they take place won't be easy, Gorman believes.

If business owners are threatened, he says, "they're probably not going to report it to the cops. The only way we're going to find out is by doing an investigation and accidentally tripping onto it. Then, during another investigation, you might be able to tie the two things together. But people who would be victimized by this wouldn't say anything for fear of their lives or their family's lives. That's what happens in Mexico a lot. People are scared to death of these cartels.